1. Field of the Invention
The exemplary embodiment relates to the backlight unit irradiating lights to the liquid crystal display device. More specially, the exemplary embodiment relates to the apparatus and method for driving light source of the backlight unit.
2. Discussion of the Related Art
Nowadays, due to the characteristics of light weight, slim thickness, low consumption electric power, the liquid crystal display device is widely applied more and more. The liquid crystal display device is applied to the portable computer such as note book PC, the official automation devices, the audio/video devices and the external/internal advertising display devices. The transparent type liquid crystal display device, the mostly used type, shows the picture data by modulating the luminescence of the light incident from the backlight unit by controlling the electric field applied to the liquid crystal layer.
For the light source of backlight unit, the fluorescent lamp such as Cold Cathode Fluorescent Lamp (CCFL) has been used. Recently, however, the light emitting diode (hereinafter “LED”) starts to be applied because it has many merits in consumption electric power, weight, luminescence and so on. The backlight unit equipped with a plurality of LED as the light source comprises an LED driver controlling the ON and OFF of the LEDs in response to the pulse width modulation (hereinafter “PWM”) signal. The conventional LED driver generally turns ON or OFF all LEDs at the same time in response to one PWM signal. Turning ON or OFF the LEDs at the same time, the amount of light irradiating to the liquid crystal display panel may be fluctuated periodically. As a result, a noise such as wavy noise can be shown in the picture or video screen on the liquid crystal display panel.